In the prior art, generally speaking, in order to fill beer or other carbonated beverage into a bottle, it has been the custom to fill the liquid via a filling tube into the bottle while the bottle interior is held under an elevated pressure. The filling operation is automatically terminated when a specified quantity of the liquid has been filled. As a filling device for use in the above-described filling operation, that of Fed. Rep. of Germany Patent No. 22341204 (corresponding to Japanese Patent Publication No. 10063/77) is publicly known.
In such a prior art counterpressure liquid filling machine, the liquid supply is automatically stopped when the pressure within the container is caused to rise as a result of the closure of a pressure gas discharge tube with a ball valve. The pressure gas discharge tube is provided through the container opening into the inside of the container and terminating at a selected depth from the opening. The ball valve is provided at a position within the container. When the bottom opening of the gas discharge tube is closed or sealed by an elevating liquid surface, the gas pressure inside the gas discharge tube increases, thus raising and actuating the ball valve to close the passage of the discharge tube.
However, in the aforementioned prior art counterpressure liquid filling machine, in which automatic measurement of the liquid is achieved by means of a ball valve which moves upward with the elevation of the liquid surface level within the discharge tube, since the tube has a bottom end at a certain distance or depth below the container opening, it is necessary, after completing the filling operation, to blow out or blast residual liquid remaining in the discharge passage to prepare for the next filling. As a result of the blowout, a blow mist is generated, which leads to problems connected with control of micro-organisms and to loss or waste of the filling liquid.
It is, therefore, an object of the current invention to obviate and remove the above-described difficulties associated with the filling operation of such liquids as beer and other refreshments: to eliminate the necessity of blowout or blast so as to cause no problems connected with control of the micro-organisms and to prevent loss or waste of filling liquid, while precisely keeping filling of the predetermined amount of liquid.